A study on the influencing factors of the global tritium breeding performance of the CFETR Helium-cooled ceramic breeder blanket

• Developed a refined 22.5 ° 3D Monte Carlo neutronics model for the CFETR HCCB blanket, enabling module-wise TBR contribution maps and detailed flux/spectral analyses. • A layered sandwich blanket raises global TBR by 8.4% (vs conventional); radial build optimization adds 2.9% (vs baseline) by strengthening Be–Li coupling and reducing parasitic absorption. • Ti-bearing choices penalize TBR (Be 12 Ti −8.9%, Li 2 TiO 3 −3.1%); increasing Be/Li packing (85%/80%) or 6 Li enrichment (95%) yields only small gains (+1.3%, +0.4%, +0.6%), favoring structural optimization. Based on the latest CFETR helium-cooled ceramic breeder (HCCB) blanket design, a three-dimensional neutronics model of a 22.5° toroidal sector was established. The Monte Carlo MCNP code was employed together with analyses of neutron flux distributions, tritium breeding and neutron multiplication reaction rates, and tritium breeding ratio (TBR) contribution maps to systematically evaluate the global tritium breeding performance as affected by structural design, material selection, pebble-bed packing fraction, 6 Li enrichment, and radial dimension. The calculations show that a layered sandwich blanket structure markedly increases TBR by 8.4%; radial dimension optimization improves TBR by about 2.9%; using Ti-containing neutron multipliers or tritium breeders reduces TBR due to neutron absorption by Ti; and simply increasing the packing fraction of functional materials or the 6 Li enrichment produces only modest TBR gains. This work provides a theoretical basis and quantitative data supporting the design and optimization of the CFETR and future HCCB blankets.